(define t-1 (let ((a 123) (b 439) (c 42)) (print (+ a b c))))
(define t-2 (let ((a 123))
	      (let ((b 439))
		(let ((c 42))
		  (print (+ a b c))))))
(define t-3 (letrec ((fact (lambda (n)
			     (if (= 0 n)
				 1
				 (* n (fact (- n 1)))))))
	      (print (fact 4))
	      (print (fact 5))
	      (print (fact 6))
	      (print (fact 7))))
